Self-cleaning electrical switch contacts for gages are known in the art as exemplified by U.S. Pat. No. 3,578,931 and others.
The objective of this invention is to improve on the prior art through the provision of a self-cleaning or wiping contact which is less expensive to manufacture and install in a gage mechanism and which will assure a wiping or cleaning action even when applied to the movable pointer of a gage operating over a very low pressure range. In such conditions, the invention will still produce a significant wiping contact between the pointer-mounted spring contact arm and the relatively stationary contact pin of either a high or low limit set contact of the gage. The invention is suitable for use on gages which must operate in very hostile environments as are found in fertilizer plants, cement plants and certain engine rooms.
A unique feature of the invention contributing to its simplicity, compactness and economy lies in the fact that companion spring wiper arms can be formed from an initially flat metal blank which, after bending, can be conveniently attached to the driven pointer of a gage in such a manner that reliability of operation is assured under all conditions.
Other features and advantages of the invention will become apparent during the course of the following description.